Directed wireless telegraphy.



E. BBLLINI & A. TOSI.

DIREGTED WIRELESS TELEGRAPHY.

APPLICATION 211.31) In. 2, 1009.

943,0 I Patented Feb. 1,1910.

F'IG L 2 raphy', of which the following is a specifica- ETTORE BELLINI AND ALESSANDRO TOSI, OF PARIS, FRANCE.

DIRECTED WIRELESS TELEGRAPHY.

Specification of Letters Patent.

Patented Feb. 1, 1910.

Application filed March 2, 1909. Serial No; 480,815.

10 all whom it may concern:

Be it known that we, ETTORE BELLINI and ALEssANnRo TosI, subjects of Italy, residing at 4 Rue du 29 J uillet, Paris, in the Republic of France, have invented new and useful Improvements in Directed Wireless Telegtion.

Systems of directed wireless telegraphy are known, which allow of emitting electric waves principally in a predetermined direction, and also of ascertaining, at the transmitting station, the direction of an unknown station emitting waves, and of receiving the waves according tosaid direction. At the transmitting station, however, the waves are not only transmitted in the direction in which it is desired to send them, but also in the diametrically opposite direction, which is of course a serious disadvantage. Similarly, at the receiving station, though it is possible to ascertain the line which traverses 0th stations, it is not possible to determine in what direction, along that line, the transmitting station is located, and in most cases information on this pointis essential. Moreover, itis impossible to prevent the reception of waves from both directions.

The present invention provides means applicable to the transmitter and the receiver in all systems of directed wireless telegraphy, which obviate the disadvantages referred to, and which enable a transmitter to direct waves solely toward a particular receiver, and a receiver to receive waves only from a selected direction and to absolutely ascertain the direction in which an unknown transmitter is located. These means consist, both as regards the transmitter and the receiver, in combining with the dirigible system a uniformly radiating system the aerial part of which is arranged substantially coincident to the symmetrical axis of the aerial of the dirigible system.

For transmission, the amplitudes of the fields of the two systems must be equal or approximately equal and the field generated by the uniform system must be approximately in phase with or in opposite phase to,

the fields generated by the dirigible system.

For receiving, the actions of both systems on the cymoscope. must be approximately eqlual, and must also be approximately in p use or in opposite phase.

In the annexed drawing Figurel dia grammatically illustrates an example in which the invention is applied to a transmitting apparatus. Fig. 2' represents the diagram which allows of determining the resultant electromagnetic field produced by the transmitting apparatus to which the invention is applied. Fig. 3 shows an example of the invention applied to a receiving apparatus. Fig. 4 is a diagram illustrating the resultant action of the receiving system on the cymoscope. a

1. Transmiss2'0n.1n the example shown in Fig. 1 the aerial of the dirigible transmitting system is an oscillation circuit which is desi nated a. In or near the symmetrical axis'ofi the aerial part of this dirigible system the antenna or aerial part b of anniformly radiating system I) is arranged. The two secondaries s and s are excited by the primaries 72 and p \Vith this combination the circular electromagnetic field due to the aerial I) is superposed on theelectromagnetic field due to the aerial a of the dirigible system. If the amplitudes of the fields of the two systems are substantially equal, and if the field generated by the uniform system is substantially in phase with or in opposition to the fields generated by the dirigible system, the resultant field will have a maximum andminimum intensity of the same direction, one at one side of the apparatus and the other at the opposite side. The direction of the maximum radiation can be ascertained, in any given installation, either by observation of the coils s p, s p, or by pre-- liminary observation of what takes place in a known receiver to which the transmission is made. \Vhen in this receiver the maximum action is observed it will be known in whatdirection the aerial of the dirigible system'must be arranged in order to transmit, with the maximum efiect, to any receiver; 3

Fig. 2 diagrammatically indicates the intensities of the three fields :a a is the field due to the system a; b is the fielddue to the system b, and c is the resultant field. It Wlll be seen in this diagram that the amplitudes of the fields of the two systems are equal, that isto say that the maximum vector radii in the diagram of the dirigible system and in the circular diagram ofthe uniformly radiatin system are equal. This is the most favora 1e condition, since the resultant field is then nil in the direction op osed to that in which transmission is to ta e place, but this state of equality may to a certain extent iii) responding vector radii of a is then obtained by adding to the uniform on by a transmitter the position of which is be departed from, since the amplitudes of the fields may not be equal, as has, already been indicated. The resultantdia am 0 is obtained b considering the field o the uniformly ra iating system, represented by b, as in .phase with the field due to the dirigible system at one side of the apparatus, represented by the half-diagran. a The curve 6 radii of b which traverse a the corresponding vector radii of a and by taking from the uniform radii which traverse a the cor- 2. Recepti0n.1n the example shown in Fig. 3 the aerial of the dirigible receivings stem is a closedoscillation circuit A.

ith this dirigible'receiving system is combined a uniformly radial receiving system the aerial B of which is substantially in the symmetrical axis of the aerial of the dirigible system. The installation is completed by two primary coils P and P and by two secondary coils S and S connected to the cymoscope R. When waves act on this apparatus a current is produced in the aerial of each ofthe two systems, and these currents act simultaneously (for example "by induction, as in the case illustrated) on the cymoscope R. The resultant action on the cymoscope difiers from that which would be roduced by the systems acting separate y. If the actions of the two receiving systems on the cymoscope are equal and in phase, the maximum efl'ect will be produced on the cymoscope"; if the said actions are equal but 0 posite the minimum effect will be produced. If a transmitter is moved in a circle around the receiver, the intensity and phase of the uniformly radiating system remain constant whereas the intensity of action on the dirigible receiving system has two maxima and two minima, and its phase changes through 180 degrees. If the effects of the two systems on the cymoscope are brought into phase, they are added when the transmitter is in the plane of the dirigible circuit, on one side;if the phases are broughtinto opposition they are subtracted when the transmitter is in the plane of the dirigible circuit on the other side. If there fore in the first instance the receiver is acted known the connections, intensities, and phases of the eflects can be so regulated thatthe maximum resultant effect, on the receiver is produced when this transmitter is in the plane of the dirigible circuit. Itwill 1 then be known which side of the dirigible feet. Thereafter, when messages are re ceived from unknown transmitters, the position in which thedirigible system mustv be placed in order to obtain the maximum efi'ect will in each case indicate the direction of the transmitter. 'mitter can also be ascertained by direct observation of the coils P S, P33 without preliminary tests. An installation of this kind can also be used to .find the direction of the transmitter. even if the effects of the two systems on the cymoscope are not perfectly equal and not exactly in phase or in opposition. v

The diagram marked Fig. 4, which is identical wlth that marked Flg. 2 illustrates at A A B and C in the case of, the recep tion the partial effects of the two independent receiving systems and of the resultant effect on the cymoscope The resultant diagramC is obtained by taking the eflect on the cymoscope ofthe uniformly radiating system as equal and in phase with the e'fl'ect.

.on-the cymoscope of the dirigible system illustrated by the half diagram A and as equal and opposed in hase to the effect on the cymoscope of the irigible system illustrated by the half diagram A The points .Of the curve C will consequently be obtained by addingto the uniform radii of B which traverse A the corresponding vector radii of A and by subtracting from the uniform radii of B which traverse A the corresponding vector radii of A. Having now described our invention, what we claim as new and desire to secure by Letters Patent is:

The direction of the trans- Means applicable to the transmittingand receiving apparatus in all systems of directed wireless telegraphy consisting in the combination of a dir1giblesystem and a uniformly radiating system the aerial part of which] is arranged substantially coincident to the symmetrical axis of the aerial of the dirigible system and the electric action of which is substantially in sition to that of the dirigib e system an has equal or substantially equal amplitudes to those of the electric action of the said dirigible system, substantially as described and for the purpose set forth.

In testimony whereof we'have signed our names to this specification in the two subscribing witnesses.

ETTORE BELLINI. ALESSANDRO TOSI.

Witnesses system must be directed. toward the transmittervin order to obtain the maximum ef- LOUIS Moses, H. 0. Con.

lphase or in o popresence of 

